And I believe that
@Camron *******
now understands that BOTH the airline bringing them here (if they're comin' in visa exempt) AND thailand when they stamp into the country at passport control CAN ask for proof of onward travel. As David Broadfoot correctly pointed out, it doesn't matter how long you "intend" to be here in the glorious "Land 'O Thaiz" it matters HOW you're entering the country (visa exempt, tourist visa, Non-Immigrant visa, etc).
Good Luck.